Iron mold



'Ro Drawing.

Patented Feb. 7, 1928.

UNITED STATES PAT T! OFFICE.

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This invention relates to an improved cast iron-permanent mold. The object/of this'mvention is to devise amold which will have the "minimumdegree of expansion and the 5 maximum degree of life, consistent with a.

high degree of'fluidity when molten. When steel contains 36% of nickel its expansion has been found to be not much more than- 25% of the normal expansion up to 'a temw perature of about;500 F.

. Steel, however, is not a very satisfectory 7 metal to use becauseit is not sufiicientl fluid to form cast molds, which is the oh ect of this invention, and if these molds have to be i 15 mifchined out of the solid the ex use is such thstfhe moldcost per castingomes ape preclable and there is then no saving over casting in sand.

. order to raise the fluidity of iron a F considerable percentage of carbonis added which. lowers the meltingpoint. In order.

that the iron should be softwhen'cast it desirable to throw the carbon out of solution,

with. the silicon. Iron containin a la amount of carbon in solution is lia 1e to'd1s.- .tortion during the operation of repeatedly casting iron in its The reason for this is that the increase of. temperature '17 .whenpouring molten iron into an iron mold.

causes the mold to expand because graphite haslessthan507 ofthespecific vi of iron and therefor e itcoinesgof a olw. T

'nickel of 34.5%, of iron 61.4%, of carbon phosphorus.

138% nickel and-the balance. chiefly iron with Application ma w re, mu. we n. 11,013.

tionthe volume of the entire mass increases and surface cracks develop, and ultimately 1 85 the mold disintegrates. V

I have found that ilgiy iron containing 2.6% silicon, 3.0% ca r n, wtotal of manganese, phosphorus and sulphur equal to 1%,

and 93.4% iron is a satisfactory material for the molds. -As nickel has a tendency to precipitate carbon, the silicon can be lowered to 2.0%. order tosecure a steel alloy of, 36.0% nickel in this cast iron, the cast iron must contain, therefore, a percentage of 45 2.0%, of silicon 1.3%,. and the balance (0.8%kwil1 consist of msnganesqsul hnr and gegsphorus. 'The" carbon is ch1' y m the state, the objection to combined carbon {being as stated. v V v WhatIelaim-is:- I v 1. A cast mold containing 34.5%-nicke],-

611% iron, 2.0% carbon (mostly free), 1.3%

silicon, ,and 0.8% oi manganese, sulphur, and

'2. A cast mold conta' 30%.

and40% nickel. M

3. A cast. mold containing from 34% to a little carbon, silicon, manganese, phosphorus, and sulphur.

In y whereof aflix my i i STANL YM. 

